OBJECTIVES: (1) We will continue our studies of mistranslation in rel mutant cells, with a view toward establishing the pattern of amino acid substitution, and understanding the role of ppGpp in maintaining translational fidelity. We also propose to study some more general features of mistranslation, pertaining to Orgel's theory of aging. (2) We will continue our investigations of a condition under which high levels of ppGpp accumulate in rel ion cells, yet stringent control of stable RNA synthesis does not occur. (3) We will isolate and characterize MS3, the new nucleotide which we suspect of being the real author of stringent control. Once it is characterized, we propose to study its effects on transcription, as well as its mechanism of synthesis, in vitro. BIBLIOGRAPHIC REFERENCES: Braedt, G., and Gallant, J. 1977. A Role of the rel Gene Product in the Control of cAMP Accumulation. J. Bact. 129:564-566. Pao, Chia C., Paietta, John, and Gallant, Jonathan A. 1977. Synthesis of Guanosine Tetraphosphate (Magic Spot I) in Saccharomyces cerevisiae. Biochem. Biophys. Res. Comm. 74:314-322.